Engine crankshaft position sensor

Abstract

An alternator assembly includes a crankshaft that is rotatable about an axis. A rotor is coupled with the crankshaft and is rotatable about the axis in conjunction with the crankshaft. A plurality of magnetic segments is disposed circumferentially about the rotor. Each of the plurality of magnetic segments includes one or more portions having one of a north or south polarity and at least one of the portions on one of the plurality of magnetic segments is configured as a datum section. The datum section has varied characteristic from the remaining one or more portions of the plurality of magnetic segments. A stator includes a plurality of stator poles that includes first and second groups of poles each having respective windings on each pole. The first and second groups are separated by a pair blank poles. A Hall Effect sensor extends between and is supported by the blank poles.

We claim: 
     
         1 . An alternator assembly comprising:
 a crankshaft rotatable about an axis;   a rotor coupled with the crankshaft and rotatable about the axis in conjunction with the crankshaft, the rotor defining a hub and a cylindrical shell extending outwardly from one end of the hub;   a plurality of magnetic segments disposed circumferentially about an interior surface of the shell, wherein each of the plurality of magnetic segments includes one or more portions having one of a north or south polarity and at least one of the portions on one of the plurality of magnetic segments configured as a datum section, the datum section having a varied characteristic from remaining one or more portions of the plurality of magnetic segments;   a stator separated from the rotor by a gap and including a plurality of stator poles, wherein the plurality of stator poles includes first and second groups of poles each having respective windings on each pole within the first and second group, the first and second groups separated by a pair blank poles; and   a Hall Effect sensor extending between and supported by the pair of blank poles, the Hall Effect sensor configured to generate signals based on a magnitude and a polarity of magnetic flux generated by each portion of the plurality of magnetic segments.   
     
     
         2 . The alternator assembly of  claim 1 , wherein the Hall Effect sensor is operably coupled with a regulator, the regulator further configured to accept current generated by rotation of the rotor relative the stator. 
     
     
         3 . The alternator assembly of  claim 1 , wherein the plurality of magnetic segments includes six magnetic segments and the six magnetic segments are disposed at equal distances about the crankshaft. 
     
     
         4 . The alternator assembly of  claim 1 , wherein the varied characteristic is configured as a variance in a thickness of the datum section from that of remaining portions of the plurality of magnetic segments thereby altering a magnetic property of the datum section relative the remaining portions. 
     
     
         5 . The alternator assembly of  claim 1 , wherein the datum section is formed from a material having different or varied magnetic properties including different elemental compositions thereby creating the varied characteristic. 
     
     
         6 . The alternator assembly of  claim 1 , wherein the datum section has reduced flux density compared to one or more of remaining portions thereby creating the varied characteristic. 
     
     
         7 . The alternator assembly of  claim 1 , wherein a polarity of each adjacent portion to the datum section may be of a common polarity. 
     
     
         8 . The alternator assembly of  claim 1 , wherein the magnetic flux generated by the rotation of the rotor relative the stator generates an altered pulse as measured by the Hall Effect sensor when the datum section passes the Hall Effect sensor compared to each remaining portion of the plurality of magnetic segments. 
     
     
         9 . The alternator assembly of  claim 8 , wherein the altered pulse is indicative of a crankshaft position and in response to receiving the crankshaft position, a controller controls an opening of a fuel injection valve and a duration over which the fuel injection valve. 
     
     
         10 . An alternator assembly comprising:
 a rotor rotatably coupled with a crankshaft about a common axis;   a first magnetic segment positioned on the rotor and including at least a first portion and a datum section separated from the first portion, the first portion having one of a north or south polarity and the datum section having varied characteristic from the first portion;   a stator separated from the rotor by a gap and including a plurality of stator poles, wherein the plurality of stator poles include first and second poles each having respective windings thereabout, the first and second stator poles separated by a pair blank stator poles; and   a Hall Effect sensor extending between and supported by the blank poles, the Hall Effect sensor configured to generate signals based on a polarity of magnetic flux generated by at least one of the first portion and the datum section.   
     
     
         11 . The alternator assembly of  claim 10 , wherein the rotor is integrally formed with a flywheel that is fixedly coupled with the crankshaft. 
     
     
         12 . The alternator assembly of  claim 10 , further comprising:
 a second magnetic segment position on an opposite side of the datum section from the first portion of the first magnetic segment and having at least a second portion adjacent to the datum section, the first portion and the second portion having a common polarity.   
     
     
         13 . The alternator assembly of  claim 10 , further comprising:
 a regulator electrically coupled with the stator and a controller, wherein the controller includes an oscillator and the controller is configured to determine a crankshaft position by receiving signals from the Hall Effect sensor and to generate inputs to operate one or more components of an engine.   
     
     
         14 . The alternator assembly of  claim 10 , wherein the varied characteristic is configured as a variance in a thickness of the datum section from that of remaining portions of the first magnetic segment thereby altering a magnetic property of the datum section relative the remaining portions. 
     
     
         15 . The alternator assembly of  claim 10 , wherein the datum section has reduced flux density compared to one or more of the remaining portions thereby creating the varied characteristic. 
     
     
         16 . A method of manufacturing an alternator assembly, the method comprising:
 forming a rotor having a hub and a shell;   assembling one or more non-magnetized segments to the rotor;   determining a plurality of magnetization orientation directions of the non-magnetized magnet portions and a varied characteristic for a datum section;   positioning the rotor within a magnetizing fixture and aligning magnetization directions of the magnet portions with a calculated direction of flux from the magnetizing fixture, wherein the datum section is aligned with a datum portion of the magnetizing fixture; and   energizing the magnetizing coils a power source.   
     
     
         17 . The method of  claim 16 , wherein the step of energizing the magnetizing coils a power source comprises an electrical connection of the power source to the magnetization fixture for a predetermined amount of time. 
     
     
         18 . The method of  claim 16 , wherein the magnetization orientation directions of the permanent magnet portions are generally aligned with a direction of flux produced by the magnetizing fixture. 
     
     
         19 . The method of  claim 16 , wherein the assembling one or more non-magnetized segments to the rotor step comprises assembling the non-magnetized permanent magnetic segments in an annular pattern on a rotor shell prior to positioning the non-magnetized permanent magnetic segments in the magnetization fixture. 
     
     
         20 . The method of  claim 16 , wherein the magnetizing fixture comprises a plurality of coils wound around a core, the coils being equal in number to a number of poles of the rotor.